Selective Inhibition of ADAR1 Using 8-Azanebularine-Modified RNA Duplexes.

Adenosine deaminases acting on RNA (ADARs) are RNA editing enzymes that catalyze the hydrolytic deamination of adenosine (A) to inosine (I) in dsRNA. In humans, two catalytically active ADARs, ADAR1 and ADAR2, perform this A-to-I editing event. The growing field of nucleotide base editing has highlighted ADARs as promising therapeutic agents while multiple studies have also identified ADAR1's role in cancer progression. However, the potential for site-directed RNA editing as well as the rational design of inhibitors is being hindered by the lack of detailed molecular understanding of RNA recognition by ADAR1. Here, we designed short RNA duplexes containing the nucleoside analog, 8-azanebularine (8-azaN), to gain insight into molecular recognition by the human ADAR1 catalytic domain. From gel shift and in vitro deamination experiments, we validate ADAR1 catalytic domain's duplex secondary structure requirement and present a minimum duplex length for binding (14 bp, with 5 bp 5' and 8 bp 3' to editing site). These findings concur with predicted RNA-binding contacts from a previous structural model of the ADAR1 catalytic domain. Finally, we establish that neither 8-azaN as a free nucleoside nor a ssRNA bearing 8-azaN inhibits ADAR1 and demonstrate that the 8-azaN-modified RNA duplexes selectively inhibit ADAR1 and not the closely related ADAR2 enzyme.

Microglial senescence contributes to female-biased neuroinflammation in the aging mouse hippocampus: implications for Alzheimer's disease.

BACKGROUND: Microglia, the brain's principal immune cells, have been implicated in the pathogenesis of Alzheimer's disease (AD), a condition shown to affect more females than males. Although sex differences in microglial function and transcriptomic programming have been described across development and in disease models of AD, no studies have comprehensively identified the sex divergences that emerge in the aging mouse hippocampus. Further, existing models of AD generally develop pathology (amyloid plaques and tau tangles) early in life and fail to recapitulate the aged brain environment associated with late-onset AD. Here, we examined and compared transcriptomic and translatomic sex effects in young and old murine hippocampal microglia. METHODS: Hippocampal tissue from C57BL6/N and microglial NuTRAP mice of both sexes were collected at young (5-6 month-old [mo]) and old (22-25 mo) ages. Cell sorting and affinity purification techniques were used to isolate the microglial transcriptome and translatome for RNA-sequencing and differential expression analyses. Flow cytometry, qPCR, and imaging approaches were used to confirm the transcriptomic and translatomic findings. RESULTS: There were marginal sex differences identified in the young hippocampal microglia, with most differentially expressed genes (DEGs) restricted to the sex chromosomes. Both sex chromosomally and autosomally encoded sex differences emerged with aging. These sex DEGs identified at old age were primarily female-biased and enriched in senescent and disease-associated microglial signatures. Normalized gene expression values can be accessed through a searchable web interface ( https://neuroepigenomics.omrf.org/ ). Pathway analyses identified upstream regulators induced to a greater extent in females than in males, including inflammatory mediators IFNG, TNF, and IL1B, as well as AD-risk genes TREM2 and APP. CONCLUSIONS: These data suggest that female microglia adopt disease-associated and senescent phenotypes in the aging mouse hippocampus, even in the absence of disease pathology, to a greater extent than males. This sexually divergent microglial phenotype may explain the difference in susceptibility and disease progression in the case of AD pathology. Future studies will need to explore sex differences in microglial heterogeneity in response to AD pathology and determine how sex-specific regulators (i.e., sex chromosomal or hormonal) elicit these sex effects.

Translatomic response of retinal Müller glia to acute and chronic stress.

Analysis of retina cell type-specific epigenetic and transcriptomic signatures is crucial to understanding the pathophysiology of retinal degenerations such as age-related macular degeneration (AMD) and delineating cell autonomous and cell-non-autonomous mechanisms. We have discovered that Aldh1l1 is specifically expressed in the major macroglia of the retina, Müller glia, and, unlike the brain, is not expressed in retinal astrocytes. This allows use of Aldh1l1 cre drivers and Nuclear Tagging and Translating Ribosome Affinity Purification (NuTRAP) constructs for temporally controlled labeling and paired analysis of Müller glia epigenomes and translatomes. As validated through a variety of approaches, the Aldh1l1cre/ERT2-NuTRAP model provides Müller glia specific translatomic and epigenomic profiles without the need to isolate whole cells. Application of this approach to models of acute injury (optic nerve crush) and chronic stress (aging) uncovered few common Müller glia-specific transcriptome changes in inflammatory pathways, and mostly differential signatures for each stimulus. The expression of members of the IL-6 and integrin-linked kinase signaling pathways was enhanced in Müller glia in response to optic nerve crush but not aging. Unique changes in neuroinflammation and fibrosis signaling pathways were observed in response to aging but not with optic nerve crush. The Aldh1l1cre/ERT2-NuTRAP model allows focused molecular analyses of a single, minority cell type within the retina, providing more substantial effect sizes than whole tissue analyses. The NuTRAP model, nucleic acid isolation, and validation approaches presented here can be applied to any retina cell type for which a cell type-specific cre is available.

Technetium-99 m-sestamibi single-photon emission computerised tomography (CT)/CT in the prediction of malignant versus benign small renal masses.

OBJECTIVES: To determine the effectiveness of technetium-99m (99m Tc)-sestamibi single-photon emission computerised tomography/computerised tomography (SPECT/CT) in distinguishing between malignant and benign renal lesions. PATIENTS AND METHODS: Between June 2018 and October 2020 all patients with new indeterminate small renal masses (SRMs) underwent 99m Tc-sestamibi renal SPECT/CT before biopsy or surgery. The accuracy of 99m Tc-sestamibi imaging diagnoses was assessed against histopathology. Receiver operating characteristic (ROC) analysis was used to determine the optimum cut-off for the tumour:normal uptake ratio. Logistic regression was used to determine if quantitative analysis significantly added to visual interpretation alone. RESULTS: A total of 74 patients with SRMs were investigated with 99m Tc-sestamibi SPECT/CT. The SPECT/CT correctly identified 49 malignant tumours and 11 benign tumours, resulting in a sensitivity of 0.89 (95% confidence interval [CI] 0.77-0.95) and a specificity of 0.73 (95% CI 0.45-0.91). The ROC analysis of uptake ratios demonstrated that a tumour:normal uptake ratio of 0.41 provided optimal diagnostic accuracy (sensitivity 0.81, specificity 0.88, area under the curve 0.883 [95% CI 0.794-0.971]). The uptake ratio was also highly significant in excluding malignancy on univariate logistic regression analysis whereby the higher the uptake ratio, the lower the chances were for malignancy (odds ratio 0.009, 95% CI 0.001-0.118, P < 0.001). However, this did not improve diagnostic accuracy when compared to visual interpretation alone. CONCLUSION: 99m Tc-sestamibi SPECT/CT is a non-invasive technique with good accuracy in determining if a SRM is benign or malignant.

Geospace Concussion: Global Reversal of Ionospheric Vertical Plasma Drift in Response to a Sudden Commencement.

An interplanetary shock can abruptly compress the magnetosphere, excite magnetospheric waves and field-aligned currents, and cause a ground magnetic response known as a sudden commencement (SC). However, the transient (<∼1 min) response of the ionosphere-thermosphere system during an SC has been little studied due to limited temporal resolution in previous investigations. Here, we report observations of a global reversal of ionospheric vertical plasma motion during an SC on 24 October 2011 using ∼6 s resolution Super Dual Auroral Radar Network ground scatter data. The dayside ionosphere suddenly moved downward during the magnetospheric compression due to the SC, lasting for only ∼1 min before moving upward. By contrast, the post-midnight ionosphere briefly moved upward then moved downward during the SC. Simulations with a coupled geospace model suggest that the reversed E ⃗ × B ⃗ vertical drift is caused by a global reversal of ionospheric zonal electric field induced by magnetospheric compression during the SC.

Ester modification at the 3' end of anti-microRNA oligonucleotides increases potency of microRNA inhibition.

MicroRNAs (miRNAs) are short noncoding RNAs that play a fundamental role in gene regulation. Deregulation of miRNA expression has a strong correlation with disease and antisense oligonucleotides that bind and inhibit miRNAs associated with disease have therapeutic potential. Current research on the chemical modification of anti-miRNA oligonucleotides (anti-miRs) is focused on alterations of the phosphodiester-ribose backbone to improve nuclease resistance and binding affinity to miRNA strands. Here we describe a structure-guided approach for modification of the 3'-end of anti-miRs by screening for modifications compatible with a nucleotide-binding pocket present on human Argonaute2 (hAgo2). We computationally screened a library of 190 triazole-modified nucleoside analogs for complementarity to the t1A-binding pocket of hAgo2. Seventeen top scoring triazoles were then incorporated into the 3' end of anti-miR21 and potency was evaluated for each in a cell-based assay for anti-miR activity. Four triazole-modified anti-miRs showed higher potency than anti-miR21 bearing a 3' adenosine. In particular, a triazole-modified nucleoside bearing an ester substituent imparted a nine-fold and five-fold increase in activity for both anti-miR21 and anti-miR122 at 300 and 5 nM, respectively. The ester group was shown to be critical as a similar carboxylic acid and amide were inactive. Furthermore, anti-miR 3' end modification with triazole-modified nucleoside analogs improved resistance to snake venom phosphodiesterase, a 3'-exonuclease. Thus, the modifications described here are good candidates for improvement of anti-miR activity.

Secretory phospholipase A2 group IIA enhances the metabolic rate and increases glucose utilization in response to thyroid hormone.

Secretory phospholipase A2 group IIA (PLA2G2A) is a phospholipase which has a role in inflammation, atherogenesis, and host defense. Previously, we found that PLA2G2A protects mice on high-fat diets from weight gain and insulin resistance. Here, we examined the regulation of PLA2G2A and the metabolic changes that occur in response to variations in thyroid status. In particular, the impact of PLA2G2A on the brown adipose tissue (BAT) thermogenic gene expression was explored. We induced hypothyroidism in C57BL/6 and PLA2G2A-overexpressing (IIA+) mice over a 10 wk period or treated them with thyroid hormone (T3) for 5 wk. There were no significant changes in PLA2G2A abundance in response to thyroid status. The energy expenditure of hypothyroid IIA+ mice did not increase; however, the energy expenditure, substrate utilization, insulin sensitivity, and glucose tolerance were all elevated in the IIA+ mice given T3. Moreover, white adipocytes from IIA+ mice were much more prone to "beiging," including increased expression of brown adipose thermogenic markers such as uncoupling protein 1 (UCP1), PR domain containing 16, and early B cell factor 2. Finally, the BAT of IIA+ mice had increased UCP1 and other proteins indicative of mitochondrial uncoupling and nonshivering adaptive thermogenesis. These data reveal a novel role for PLA2G2A on adipose tissue thermogenesis depending on thyroid status.-Kuefner, M. S., Deng, X., Stephenson, E. J., Pham, K., Park, E. A. Secretory phospholipase A2 group IIA enhances the metabolic rate and increases glucose utilization in response to thyroid hormone.

Small soft tissue masses indeterminate at imaging: histological diagnoses at a tertiary orthopedic oncology clinic.

OBJECTIVE: To review histologic diagnoses of soft-tissue masses (STMs) ≤ 2 cm with indeterminate imaging features encountered in musculoskeletal oncology clinic at a tertiary referral center. MATERIALS AND METHODS: This was an IRB-approved retrospective review of patients with STMs ≤ 2 cm, referred to our tertiary care orthopedic oncology clinic over 4.75 consecutive years. Maximum diameter was based on imaging measurement by a fellowship-trained musculoskeletal radiologist. Simple lipomas, synovial cysts, metastases, and cases without histologic confirmation were excluded. Patient demographics, tumor imaging features (location, depth, size, and tumor:muscle enhancement and T2 signal ratios), and histology were recorded and compared. RESULTS: Mean maximum diameter for 42 trunk/extremity STMs was 1.5 cm (range, 0.7 to 2 cm). Mean age was 48 years (range, 18-83 years). Nine (21%) of the masses were malignant, while 33 (79%) were non-malignant. Thirty-nine (93%) of masses were superficial; 7/39 (18%) of these superficial tumors were malignant. Malignancy was not associated with underlying vessels, tendon, or fascia (p = 0.19). The non-malignant vs. malignant tumor:muscle enhancement ratio was 2.15 vs. 2.32 (p = 0.58) and enhancement coefficient of variation was 0.14 vs. 0.10 (p = 0.29). Most common malignant histologic subtypes were synovial sarcoma (n = 3), fibroblastic/myofibroblastic sarcoma (n = 2), leiomyosarcoma (n = 2), myxofibrosarcoma (n = 1), and angiomatoid fibrous histiocytoma (n = 1). The majority (67%) of non-malignant lesions were: leiomyoma (n = 6), angiomyoma (n = 5), schwannoma (n = 4), benign fibrous histiocytoma (n = 4), and hemangioma (n = 3). CONCLUSIONS: At a tertiary musculoskeletal oncology referral clinic, primary STMs ≤ 2 cm with indeterminate imaging features should be managed cautiously despite their small size and/or superficial location.

Pyrophosphate Supplementation Prevents Chronic and Acute Calcification in ABCC6-Deficient Mice.

Soft tissue calcification occurs in several common acquired pathologies, such as diabetes and hypercholesterolemia, or can result from genetic disorders. ABCC6, a transmembrane transporter primarily expressed in liver and kidneys, initiates a molecular pathway inhibiting ectopic calcification. ABCC6 facilitates the cellular efflux of ATP, which is rapidly converted into pyrophosphate (PPi), a major calcification inhibitor. Heritable mutations in ABCC6 underlie the incurable calcification disorder pseudoxanthoma elasticum and some cases of generalized arterial calcification of infancy. Herein, we determined that the administration of PPi and the bisphosphonate etidronate to Abcc6-/- mice fully inhibited the acute dystrophic cardiac calcification phenotype, whereas alendronate had no significant effect. We also found that daily injection of PPi to Abcc6-/- mice over several months prevented the development of pseudoxanthoma elasticum-like spontaneous calcification, but failed to reverse already established lesions. Furthermore, we found that the expression of low amounts of the human ABCC6 in liver of transgenic Abcc6-/- mice, resulting in only a 27% increase in plasma PPi levels, led to a major reduction in acute and chronic calcification phenotypes. This proof-of-concept study shows that the development of both acute and chronic calcification associated with ABCC6 deficiency can be prevented by compensating PPi deficits, even partially. Our work indicates that PPi substitution represents a promising strategy to treat ABCC6-dependent calcification disorders.

Secretory phospholipase A2 group IIA modulates insulin sensitivity and metabolism.

Secretory phospholipase A2 group IIA (PLA2G2A) is a member of a family of secretory phospholipases that have been implicated in inflammation, atherogenesis, and antibacterial actions. Here, we evaluated the role of PLA2G2A in the metabolic response to a high fat diet. C57BL/6 (BL/6) mice do not express PLA2g2a due to a frameshift mutation. We fed BL/6 mice expressing the human PLA2G2A gene (IIA+ mice) a fat diet and assessed the physiologic response. After 10 weeks on the high fat diet, the BL/6 mice were obese, but the IIA+ mice did not gain weight or accumulate lipid. The lean mass in chow- and high fat-fed IIA+ mice was constant and similar to the BL/6 mice on a chow diet. Surprisingly, the IIA+ mice had an elevated metabolic rate, which was not due to differences in physical activity. The IIA+ mice were more insulin sensitive and glucose tolerant than the BL/6 mice, even when the IIA+ mice were provided the high fat diet. The IIA+ mice had increased expression of uncoupling protein 1 (UCP1), sirtuin 1 (SIRT1), and PPARγ coactivator 1α (PGC-1α) in brown adipose tissue (BAT), suggesting that PLA2G2A activates mitochondrial uncoupling in BAT. Our data indicate that PLA2G2A has a previously undiscovered impact on insulin sensitivity and metabolism.

Streptozotocin diabetes increases mRNA expression of ketogenic enzymes in the rat heart.

BACKGROUND: Diabetic cardiomyopathy develops in insulin-dependent diabetic patients who have no hypertension, cardiac hypertrophy or vascular disease. Diabetes increases cardiac fatty acid oxidation, but cardiac hypertrophy limits fatty acid oxidation. Here we examined effects of diabetes on gene expression in rat hearts. METHODS: We used oligonucleotide microarrays to examine effects of insulindependent diabetes in the rat heart. RTQ PCR confirmed results of microarrays. Specific antibodies were used to examine changes in the mitochondrial 3-hydroxy-3-methylglutaryl-CoA synthase 2 (HMGCS2). RESULTS: A surprising result of diabetes was increased mRNA encoding all enzymes of the ketone body synthesis pathway. Increased mRNA expression for these enzymes was confirmed by RTQ PCR. The mRNA encoding HMGCS2, the rate-controlling enzyme, was 27 times greater in diabetic hearts. Total HMGCS2 protein increased 8-fold in diabetic hearts, but no difference was found in HMGCS2 protein in control vs. diabetic liver. CONCLUSIONS: Insulin-dependent diabetes induced the enzymes of ketone body synthesis in the heart, including HMGCS2, as well as increasing enzymes of fatty acid oxidation. GENERAL SIGNIFICANCE: The mammalian heart does not export ketone bodies to other tissues, but rather is a major consumer of ketone bodies. Induction of HMGCS2, which is normally expressed only in the fetal and newborn heart, may indicate an adaptation by the heart to combat "metabolic inflexibility" by shifting the flux of excess intramitochondrial acetyl-CoA derived from elevated fatty acid oxidation into ketone bodies, liberating free CoA to balance the acetyl-CoA/CoA ratio in favor of increased glucose oxidation through the pyruvate dehydrogenase complex.

Calculating protein-ligand binding affinities with MMPBSA: Method and error analysis.

Molecular Mechanics Poisson-Boltzmann Surface Area (MMPBSA) methods have become widely adopted in estimating protein-ligand binding affinities due to their efficiency and high correlation with experiment. Here different computational alternatives were investigated to assess their impact to the agreement of MMPBSA calculations with experiment. Seven receptor families with both high-quality crystal structures and binding affinities were selected. First the performance of nonpolar solvation models was studied and it was found that the modern approach that separately models hydrophobic and dispersion interactions dramatically reduces RMSD's of computed relative binding affinities. The numerical setup of the Poisson-Boltzmann methods was analyzed next. The data shows that the impact of grid spacing to the quality of MMPBSA calculations is small: the numerical error at the grid spacing of 0.5 Å is already small enough to be negligible. The impact of different atomic radius sets and different molecular surface definitions was further analyzed and weak influences were found on the agreement with experiment. The influence of solute dielectric constant was also analyzed: a higher dielectric constant generally improves the overall agreement with experiment, especially for highly charged binding pockets. The data also showed that the converged simulations caused slight reduction in the agreement with experiment. Finally the direction of estimating absolute binding free energies was briefly explored. Upon correction of the binding-induced rearrangement free energy and the binding entropy lost, the errors in absolute binding affinities were also reduced dramatically when the modern nonpolar solvent model was used, although further developments were apparently necessary to further improve the MMPBSA methods. © 2016 Wiley Periodicals, Inc.

Tapping a bacterial enzymatic pathway for the preparation and manipulation of synthetic nanomaterials.

We present a spherical micelle generated in a three-step sequence in which a farnesyl-pantetheine conjugate is phosphorylated, adenylated, and phosphorylated once more to generate a farnesyl-CoA amphiphile that self-assembles into spherical micelles. A sphere-to-fibril morphological switch is achieved by enzymatically transferring the farnesyl group of the farnesyl-CoA micelle onto a peptide via phosphopantetheinyl transferase to generate a peptide amphiphile. Each step in the sequence is followed with characterization by HPLC, MS, TEM, and DLS. This system offers an entry into cofactor-mediated peptide decoration by extending the principles of bioresponsive polymeric materials to sequential enzyme cascades.

Postoperative Opioid-Prescribing Practice in Limb Preservation Surgery.

BACKGROUND: Limb preservation surgery affects more than 100,000 Americans annually. Current postoperative pain management prescribing practices of podiatric physicians in the United States are understudied. We examined prescribing practices for limb preservation surgery to identify prescriber characteristics' that may be associated with postoperative opioid-prescribing practices. METHODS: We administered an anonymous online questionnaire consisting of five patient scenarios with limb preservation surgery commonly performed by podiatric physicians. Respondents provided information about their prescription choice for each surgery. Basic provider demographics were collected. We developed linear regression models to identify the strength and direction of association between prescriber characteristics and quantity of postoperative opioid "pills" (dosage units) prescribed at surgery. Logistic regression models were used to identify the odds of prescribing opioids for each scenario. RESULTS: One hundred fifteen podiatric physicians completed the survey. Podiatric physicians reported using regional nerve blocks 70% to 88% of the time and prescribing opioids 43% to 67% of the time across all scenarios. Opioids were more commonly prescribed than nonsteroidal anti-inflammatory drugs and anticonvulsants. Practicing in the Northeast United States was a significant variable in linear regression (P = .009, a decrease of 9-10 dosage units) and logistic regression (odds ratio, 0.23; 95% confidence interval, 0.07-0.68; P = .008) models for the transmetatarsal amputation scenario. CONCLUSIONS: Prescribing practice variation exists in limb preservation surgery by region. Podiatric physicians reported using preoperative regional nerve blocks more than prescribing postoperative opioids for limb preservation surgeries. Through excess opioid prescribing, the diabetes pandemic has likely contributed to the US opioid epidemic. Podiatric physicians stand at the intersection of these two public health crises and are equipped to reduce their impact via preventive foot care and prescribing nonopioid analgesics when warranted.

Age- and sex- divergent translatomic responses of the mouse retinal pigmented epithelium.

Aging is the main risk factor for age-related macular degeneration (AMD), a retinal neurodegenerative disease that leads to irreversible blindness, particularly in people over 60 years old. Retinal pigmented epithelium (RPE) atrophy is an AMD hallmark. Genome-wide chromatin accessibility, DNA methylation, and gene expression studies of AMD and control RPE demonstrate epigenomic/transcriptomic changes occur during AMD onset and progression. However, mechanisms by which molecular alterations of normal aging impair RPE function and contribute to AMD pathogenesis are unclear. Here, we specifically interrogate the RPE translatome with advanced age and across sexes in a novel RPE reporter mouse model. We find differential age- and sex- associated transcript expression with overrepresentation of pathways related to inflammation in the RPE. Concordant with impaired RPE function, the phenotypic changes in the aged translatome suggest that aged RPE becomes immunologically active, in both males and females, with some sex-specific signatures, which supports the need for sex representation for in vivo studies.

Flow Cytometry Analysis of Microglial Phenotypes in the Murine Brain During Aging and Disease.

Microglia, the brain's primary resident immune cell, exists in various phenotypic states depending on intrinsic and extrinsic signaling. Distinguishing between these phenotypes can offer valuable biological insights into neurodevelopmental and neurodegenerative processes. Recent advances in single-cell transcriptomic profiling have allowed for increased granularity and better separation of distinct microglial states. While techniques such as immunofluorescence and single-cell RNA sequencing (scRNA-seq) are available to differentiate microglial phenotypes and functions, these methods present notable limitations, including challenging quantification methods, high cost, and advanced analytical techniques. This protocol addresses these limitations by presenting an optimized cell preparation procedure that prevents ex vivo activation and a flow cytometry panel to distinguish four distinct microglial states from murine brain tissue. Following cell preparation, fluorescent antibodies were applied to label 1) homeostatic, 2) disease-associated (DAM), 3) interferon response (IRM), and 4) lipid-droplet accumulating (LDAM) microglia, based on gene markers identified in previous scRNA-Seq studies. Stained cells were analyzed by flow cytometry to assess phenotypic distribution as a function of age and sex. A key advantage of this procedure is its adaptability, allowing the panel provided to be enhanced using additional markers with an appropriate cell analyzer (i.e., Cytek Aurora 5 laser spectral flow cytometer) and interrogating different brain regions or disease models. Additionally, this protocol does not require microglial cell sorting, resulting in a relatively quick and straightforward experiment. Ultimately, this protocol can compare the distribution of microglial phenotypic states between various experimental groups, such as disease state or age, with a lower cost and higher throughput than scRNA-seq. Key features • Analysis of microglial phenotypes from murine brain without the need for cell sorting, imaging, or scRNA-seq. • This protocol can distinguish between homeostatic, disease-associated (DAM), lipid-droplet accumulating (LDAM), and interferon response (IRM) microglia from any murine brain region and/or disease model of interest. • This protocol can be modified to incorporate additional markers of interest or dyes when using a cell analyzer capable of multiple color detections.

A randomized comparison between bifurcation and prebifurcation subparaneural popliteal sciatic nerve blocks.

BACKGROUND: In this prospective, randomized, observer-blinded trial, we compared ultrasound-guided subparaneural popliteal sciatic nerve blocks performed either at or proximal to the neural bifurcation (B). We hypothesized that the total anesthesia-related time (sum of performance and onset times) would be decreased with the prebifurcation (PB) technique. METHODS: Ultrasound-guided posterior popliteal sciatic nerve block was performed in 68 patients. All subjects received an identical volume (30 mL) and mix of local anesthetic agent (1% lidocaine-0.25% bupivacaine-5 µg/mL epinephrine). In the PB group, the local anesthetic solution was deposited at the level of the common sciatic trunk, just distal to the intersection between its circular and elliptical sonographic appearances, inside the paraneural sheath. In the B group, the injection was performed inside the sheath between the tibial and peroneal divisions. A blinded observer recorded the success rate (complete tibial and peroneal sensory block at 30 minutes) and onset time. The performance time, number of needle passes, and adverse events (paresthesia, neural edema) were also recorded. All subjects were contacted 7 days after the surgery to inquire about the presence of persistent numbness or motor deficit. RESULTS: Both techniques resulted in comparable success rates (85%-88%; 95% confidence interval [CI] of the intergroup difference, -14% to 19%) and required similar performance times (8.1 minutes; 95% CI of the difference, -1.65 to 1.71 minutes), onset times (15.0-17.7 minutes; 95% CI of the difference, -7.65 to 2.31 minutes), and total anesthesia-related times (23.4-26.0 minutes; 95% CI of the difference, -7.83 to 2.74 minutes). The number of needle passes and incidence of paresthesia (25%-34%) were also similar between the 2 groups. Sonographic neural swelling was detected in 2 and 3 subjects in the PB and B groups, respectively. In all 5 cases, the needle was carefully withdrawn and the injection completed uneventfully. Patient follow-up 1 week after the surgery revealed 2 patients with residual numbness. In both instances, the latter had resolved by 1 month. CONCLUSION: When local anesthetic is injected inside the paraneural sheath, B and PB posterior popliteal sciatic nerve blocks result in comparable success and total anesthesia-related times. However, in light of the 95% CIs, we cannot exclude the possibility that an intergroup difference of 19% and 7.83 minutes might have gone undetected for success rate and total time, respectively.

Multiple Myeloma in Adolescent and Young Adults: An ASCO CancerLinQ and SEER Analysis.

BACKGROUND: Multiple myeloma (MM) is exceedingly rare in adolescents and young adults (AYAs) < 45 years of age. METHODS: Real-world data from ASCO's CancerLinQ DiscoveryⓇ (CLQD) MM dataset and SEER were utilized to characterize demographics and outcomes of AYA MM patients in the United States in the modern treatment era. Frequencies of SPMs, VTEs, and infections were assessed, as were OS and cause of death. RESULTS: A total of 1946 AYA MM patients from SEER and 1334 from CancerLinQ were included. In terms of SPMs, AYAs were more likely to develop ALL (RR 2.6, P = .003) and AML (RR 1.7, P = .034), and less likely to develop nonmelanoma skin cancer (RR 0.2, P = .001) and prostate cancer (RR 0.1, P = .013) than MM patients ≥ 45. AYAs were at lower risk of VTE (RR 0.75, P = .002) and slightly higher risk of infections (RR 1.11, P = .002). Median OS among AYA MM patients was significantly longer than MM patients ≥ 45 in both datasets. In the SEER cohort, female sex (HR 0.74, P = .003), non-Hispanic ethnicity (HR 0.73, P = .005), and annual household income ≥ $65,000 per year (HR 0.67, P = .001) were associated with lower hazards of mortality. In the CLQD cohort, OS was significantly influenced by female sex (HR 0.6, P = .048). Race did not have a statistically significant impact OS in either cohort. Most AYAs died of MM (68.3%), other primary malignancy (7.5%, mostly leukemia), and cardiovascular events (5.2%). Infections accounted for 3.2% of deaths. CONCLUSION: This analysis highlights some unique characteristics of AYA MM patients in the United States in the modern era.